Memoized backchain <= is renamed to <- to avoid conflict with extensive downstream use of <=/2 to mean reverse implication.. Historically '<-' had meant what is now know as ":-" being unused it was borrowed as it means "Backchaining"

Added Macro Transform =@=> so instead of asserting the Anteceedant to assert the Consequent
@TODO - MANY MORE CHANGES TO WRITE - for now back to coding...
@TODO = Added Cutted Forward Chaining =!=> as a signal to stop processing rules on first success

The Pfc system is a package that provides a forward reasoning capability to be used together with conventional Prolog programs. The Pfc inference rules are Prolog terms which are asserted as clauses into the regular Prolog database. When new facts or forward reasoning rules are added to the Prolog database (via a special predicate add/1, forward reasoning is triggered and additional facts that can be deduced via the application of the forward chaining rules are also added to the database. A simple justification-based truth-maintenance system is provided as well as simple predicates to explore the resulting proof trees.